Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disorder affecting adults older than 50 years, characterized by pain and stiffness involving the shoulder and pelvic girdles, with elevated inflammatory markers and a dramatic response to low-dose corticosteroids.
PMR is closely associated with Giant Cell Arteritis (GCA), and the two conditions may occur together.
Etiology
Cause is unknown.
Possible factors:
- Genetic predisposition (HLA-DR4)
- Environmental triggers
- Viral infections (proposed)
- Immune-mediated inflammation
Pathophysiology
Inflammation mainly affects:
- Synovium
- Bursa (especially subacromial and trochanteric bursae)
- Tendons
Unlike inflammatory myopathies:
- Muscle fibers are normal
- Pain arises from periarticular inflammation rather than muscle destruction.
Major cytokines:
- IL-6
- IL-1
- TNF-α
Clinical Features
Symptoms
Pain
Usually bilateral involving:
- Shoulders (most common)
- Neck
- Upper arms
- Hip girdle
- Thighs
Pain is:
- Aching
- Symmetrical
- Worse in morning
Morning stiffness
Typically:
- Lasts >45 minutes
- Difficulty:
- Getting out of bed
- Raising arms
- Climbing stairs
- Combing hair
- Dressing
Constitutional symptoms
May include:
- Low-grade fever
- Malaise
- Fatigue
- Weight loss
- Loss of appetite
- Depression
Association with Giant Cell Arteritis
Approximately:
- 15–20% of PMR patients develop GCA.
- Around 40–60% of GCA patients have PMR symptoms.
Symptoms suggesting GCA
- New-onset headache
- Jaw claudication
- Scalp tenderness
- Visual disturbance
- Diplopia
- Sudden vision loss (medical emergency)
Investigations
Blood tests
Elevated inflammatory markers
- ESR ↑ (often >40 mm/hr)
- CRP ↑
CBC
May show:
- Normocytic anemia
- Thrombocytosis
Others
- Liver enzymes (ALP) may be mildly elevated.
- CK is normal (helps distinguish from myositis).
Autoantibodies
Usually negative:
- Rheumatoid factor (RF)
- Anti-CCP
- ANA
Imaging
Ultrasound
May demonstrate:
- Subdeltoid bursitis
- Biceps tenosynovitis
- Hip synovitis
- Trochanteric bursitis
MRI
Useful if diagnosis is uncertain.
PET-CT
Can identify associated large-vessel vasculitis.
Diagnostic Criteria (2012 ACR/EULAR Classification)
Required:
- Age ≥50 years
- Bilateral shoulder pain
- Elevated ESR or CRP
Additional features include:
- Morning stiffness >45 minutes
- Hip pain or limited range of motion
- Negative RF/anti-CCP
- Absence of other joint involvement
- Ultrasound findings supportive of PMR
Management
First-line treatment
Prednisolone
Typical starting dose:
- 12.5–25 mg orally once daily (commonly 15 mg/day)
Expected response:
- Significant improvement within 24–72 hours
- Lack of improvement should prompt reconsideration of the diagnosis.
Steroid taper
A common approach:
- Maintain initial dose for 2–4 weeks after symptom control.
- Reduce gradually to 10 mg/day over several weeks.
- Then taper by about 1 mg every 1–2 months if stable.
- Total treatment duration is often 1–2 years, individualized by symptoms and inflammatory markers.
Steroid-sparing therapy
Consider in recurrent disease or when steroid toxicity is a concern:
- Methotrexate
- An IL-6 inhibitor such as Sarilumab may be used in selected patients with refractory or relapsing PMR.
Bone protection
Because prolonged corticosteroid therapy increases fracture risk:
- Calcium supplementation
- Vitamin D supplementation
- Consider bisphosphonates in patients at moderate or high fracture risk.
